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Does the viral subtype influence the biennial cycle of respiratory syncytial virus?

Mlinaric-Galinovic G, Vojnovic G, Cepin-Bogovic J, Bace A, Bozikov J, Welliver RC, Wahn U, Cebalo L - Virol. J. (2009)

Bottom Line: The predominant subtype in both outbreaks was RSV subtype B.Not until November 2007 did RSV subtype A predominate, while initiating a new outbreak continuing into the following calendar year.Though only two calendar years were monitored, we believe that the biennial RSV cycle in Croatia occurs independently of the dominant viral subtype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Virology, Croatian National Institute of Public Health and University Medical School of Zagreb, Zagreb, Croatia. gordana.galinovic@hzjz.hr

ABSTRACT

Background: The epidemic pattern of respiratory syncytial virus (RSV) is quite different in regions of Europe (biennial epidemics in alternating cycles of approximately 9 and 15 months) than in the Western Hemisphere (annual epidemics). In order to determine if these differences are accounted for by the circulation of different RSV subtypes, we studied the prevalence of RSV subtype A and B strains in Zagreb County from 1 January 2006 to 31 December 2007.

Results: RSV was identified in the nasopharyngeal secretions of 368 inpatients using direct fluorescence assays and/or by virus isolation in cell culture. The subtype of recovered strains was determined by real-time PCR. Of 368 RSV infections identified in children during this interval, subtype A virus caused 94 infections, and subtype B 270. Four patients had a dual RSV infection (subtypes A and B). The period of study was characterized by two epidemic waves of RSV infections-one, smaller, in the spring of 2006 (peaking in March), the second, larger, in December 2006/January 2007 (peaking in January). The predominant subtype in both outbreaks was RSV subtype B. Not until November 2007 did RSV subtype A predominate, while initiating a new outbreak continuing into the following calendar year.

Conclusion: Though only two calendar years were monitored, we believe that the biennial RSV cycle in Croatia occurs independently of the dominant viral subtype.

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Bronchiolitis and pneumonia (No.) caused by respiratory syncytial virus in Croatia in 2006 and 2007 by viral subtype and age.
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Figure 1: Bronchiolitis and pneumonia (No.) caused by respiratory syncytial virus in Croatia in 2006 and 2007 by viral subtype and age.

Mentions: Bronchiolitis was caused by subtype B virus in 131/173 (75.7%) patients with this diagnosis, of whom 123 were infants (93.89%). Bronchiolitis was caused by RSV subtype A in 40 patients (23.1%), of whom 37 were infants (92.50%, Figure 1). Subtype B caused severe LRTIs (bronchiolitis and pneumonia) in 159/270 (58.9%) of those subjects with proved infections caused by this subtype. Subtype A caused bronchiolitis or pneumonia in 49/94 cases (52.1%, p = 0.25, Table 1).


Does the viral subtype influence the biennial cycle of respiratory syncytial virus?

Mlinaric-Galinovic G, Vojnovic G, Cepin-Bogovic J, Bace A, Bozikov J, Welliver RC, Wahn U, Cebalo L - Virol. J. (2009)

Bronchiolitis and pneumonia (No.) caused by respiratory syncytial virus in Croatia in 2006 and 2007 by viral subtype and age.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742548&req=5

Figure 1: Bronchiolitis and pneumonia (No.) caused by respiratory syncytial virus in Croatia in 2006 and 2007 by viral subtype and age.
Mentions: Bronchiolitis was caused by subtype B virus in 131/173 (75.7%) patients with this diagnosis, of whom 123 were infants (93.89%). Bronchiolitis was caused by RSV subtype A in 40 patients (23.1%), of whom 37 were infants (92.50%, Figure 1). Subtype B caused severe LRTIs (bronchiolitis and pneumonia) in 159/270 (58.9%) of those subjects with proved infections caused by this subtype. Subtype A caused bronchiolitis or pneumonia in 49/94 cases (52.1%, p = 0.25, Table 1).

Bottom Line: The predominant subtype in both outbreaks was RSV subtype B.Not until November 2007 did RSV subtype A predominate, while initiating a new outbreak continuing into the following calendar year.Though only two calendar years were monitored, we believe that the biennial RSV cycle in Croatia occurs independently of the dominant viral subtype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Virology, Croatian National Institute of Public Health and University Medical School of Zagreb, Zagreb, Croatia. gordana.galinovic@hzjz.hr

ABSTRACT

Background: The epidemic pattern of respiratory syncytial virus (RSV) is quite different in regions of Europe (biennial epidemics in alternating cycles of approximately 9 and 15 months) than in the Western Hemisphere (annual epidemics). In order to determine if these differences are accounted for by the circulation of different RSV subtypes, we studied the prevalence of RSV subtype A and B strains in Zagreb County from 1 January 2006 to 31 December 2007.

Results: RSV was identified in the nasopharyngeal secretions of 368 inpatients using direct fluorescence assays and/or by virus isolation in cell culture. The subtype of recovered strains was determined by real-time PCR. Of 368 RSV infections identified in children during this interval, subtype A virus caused 94 infections, and subtype B 270. Four patients had a dual RSV infection (subtypes A and B). The period of study was characterized by two epidemic waves of RSV infections-one, smaller, in the spring of 2006 (peaking in March), the second, larger, in December 2006/January 2007 (peaking in January). The predominant subtype in both outbreaks was RSV subtype B. Not until November 2007 did RSV subtype A predominate, while initiating a new outbreak continuing into the following calendar year.

Conclusion: Though only two calendar years were monitored, we believe that the biennial RSV cycle in Croatia occurs independently of the dominant viral subtype.

Show MeSH
Related in: MedlinePlus